##### http://autoconf-archive.cryp.to/ac_cxx_complex_math_in_namespace_std.html
#
# SYNOPSIS
#
#   AC_CXX_COMPLEX_MATH_IN_NAMESPACE_STD
#
# DESCRIPTION
#
#   If the C math functions are in the cmath header file and std::
#   namespace, define HAVE_MATH_FN_IN_NAMESPACE_STD.
#
# LAST MODIFICATION
#
#   2004-02-04
#
# COPYLEFT
#
#   Copyright (c) 2004 Todd Veldhuizen
#   Copyright (c) 2004 Luc Maisonobe <luc@spaceroots.org>
#
#   Copying and distribution of this file, with or without
#   modification, are permitted in any medium without royalty provided
#   the copyright notice and this notice are preserved.

AC_DEFUN([AC_CXX_COMPLEX_MATH_IN_NAMESPACE_STD],
[AC_CACHE_CHECK(whether complex math functions are in std::,
ac_cv_cxx_complex_math_in_namespace_std,
[AC_REQUIRE([AC_CXX_NAMESPACES])
 AC_LANG_SAVE
 AC_LANG_CPLUSPLUS
 AC_TRY_COMPILE([#include <complex>
namespace S { using namespace std;
              complex<float> pow(complex<float> x, complex<float> y)
              { return std::pow(x,y); }
            };
],[using namespace S; complex<float> x = 1.0, y = 1.0; S::pow(x,y); return 0;],
 ac_cv_cxx_complex_math_in_namespace_std=yes, ac_cv_cxx_complex_math_in_namespace_std=no)
 AC_LANG_RESTORE
])
if test "$ac_cv_cxx_complex_math_in_namespace_std" = yes; then
  AC_DEFINE(HAVE_COMPLEX_MATH_IN_NAMESPACE_STD,,
            [define if complex math functions are in std::])
fi
])
